Leg height adjuster



April 24, 1962 D. G. COSTAR LEG HEIGHT ADJUSTER Filed Sept. 2, 1960 United States Patent 3,030,730 LEG HEIGHT ADJUSTER Don G. Costar, 336 W. 11th St., Reno, Nev. Filed Sept. 2, 1960, Ser. No. 53,650 4 Claims. (Cl. 45-139) This invention relates to height adjusters, in general, and in particular to a shoring device which compensates for legs of uneven length in furniture or the like, or for uneven floor surfaces accommodating such legs, or a combination of both.

The problem involved is an ever-present one, and al- .though many proposals have been made in the past for an orderly and workable solution, clumsy expedients, improvised on the spot, still prevail. For instance, a package of book-type matches is commonly employed as a compensating wedge in the space under a table leg. Needless to say, this is not only unsightly, but represents a distinct hazard. Another device which, although intolerable in a well-regulated home, but frequently resorted to in public eating places, is to wedge a fork or other article of silverware under the table leg.

I have found that a simple, yet effective, solution of the problem is to be had in the employment of a cooperating pair of wedges with mating serrations whereby shoring up may be accomplished to the necessary degree in any of several stepwise positions of adjustment. Since the height of adjustment seldom exceeds a reasonably small maximum value, the compensating device may be correspondingly small in dimensions. Also by the use of modern plastics it may be simple, inexpensive of manufacture, and low in cost.

It is therefore an object of the invention to provide a compensating device for shoring furniture legs which is operable over a stepwise range of adjustment, and keyed in position when set. Also among the objects it is the aim to provide such a device which is simple, yet efiicient and reliable in operation, of reasonably small dimensions, easy of manufacture, and low in cost.

These and other objects are attained by the invention, a preferred form of which is described in the following specification, and illustrated in the drawings, in which:

FIGURE 1 is a fragmentary view, in perspective, showing the lower end of a table leg resting on the pair of compensating wedges,

FIGURE 2 is a view in partial section through the wedges, as seen along the line 2--2 of FIGURE 1,

FIGURE 3 is a sectional view taken on the plane of the line 33 of FIGURE 2, and

FIGURE 4 is a schematic view of the wedge assembly showing two positions of adjustment.

Referring to the drawings by characters of reference, there is shown the lower portion of a round table leg having a central, rounded, bearing head 12, for easy sliding, which is secured in place by a pointed shank 14. As seen in FIGURE 2, the bottom 16 of the leg 10 is spaced from the door line 18, and this distance is compensated by the pair of wedges, comprising an upper wedge 20 and a lower wedge 22, the wedges being identical, but inverted with respect to one another. Each of the wedges, which are preferably cylindrical, that is, of circular form as viewed in plan (in an axial direction), has a series of parallel troughs 24 and crests 26 arranged in the sense of parallel chords of the wedge circle, and as seen in FIG- URE 2, the crests and troughs have a serrated or sawtooth form, as viewed edgewise. It will be noted that these mating serrations which have sides of equal length, and may therefore be described as isosceles, permit of stepwise, adjusted positions of the respective wedges in two directions, with resulting variation in the effective height of the wedge assembly, and also key or lock the parts against retrograde sliding. Thus, it will be noted in the schematic showing in FIGURE 4, wherein the same reference characters have been employed for the wedges as in FIGURES 1 to 3, when the top wedge is superposed on the lower so that the two are co-axial and coincide as to periphery, the compensating wedge system is at its lowest height, indicated by A. However, when the upper wedge 20 is moved a distance C in a direction transverse to the serrations, shown as the distance between the initial and final positions of the axis of wedge 20, the overall height of the combination increases from A to B. Conveniently, in the actual adjusting operation, the wedges, set at minimum height will be slipped into the space under the nonconforming chair leg, and the top wedge then moved across the crests of the saw teeth and up the slope of the lower wedge, until the first resistance is encountered by the meeting of the top wedge with the bottom of the table leg or its bearing. Following this con-tact, one further stage of movement across the crests of the serrations should be sufficient to complete the shoring-up process, but proper results may be obtained with more or less movement than this, depending on several factors, such as the degree of slope of the wedges and the hardness or resiliency of the contact surfaces. Of course it is also possible to try several positions of adjustment of the wedges, lifting and dropping the table leg for each trial.

Each wedge has a frusto-spherical concavity-28 in the face opposite the serrated face. When the wedge is in the upper position, such as wedge 20, this concavity opens upwardly and acts as a receiver for the table leg or its bearing head, thus defeating any tendency for the leg to slip sidewise oil? the wedge assembly. When the wedge is in the lower position, such as wedge 22, the concavity opens downwardly and functions as a vacuum cup to prevent movement of the lower wedge on the floor surface. This is particularly important in the case where adjustment of the wedges is accomplished by riding one set of serrations over the other. The vacuum effect will depend upon the physical properties of the material of the wedges. Generally speaking, a plastic material is preferable, and in this class many materials will be found suitable for the gripping action.

It will be seen that I have provided a compensating device which is not only simple of operation and capable of fine adjustment in stages, but which is securely keyed or locked against retrograde movement after setting, and that these are accomplished by means of a single, basic structural unit, without extraneous parts.

Having thus described my invention, what I desire to claim by Letters Patent is:

l. A height compensating device for table legs and the like comprising a pair of identical wedges, each of generally right-circular, cylindrical form, with one face perpendicular to the cylinder axis and having a frustospherical concavity concentric with said axis, the opposite face having a continuous series of parallel, isosceles serrations arranged chord-wise of the cylinder, the crest-s and troughs of said serrations lying in a pair of parallel planes, said planes angularly disposed with respect to said one face.

2. A height compensating device for table legs and the like comprising a pair of identical wedges, each of generally right-circular, cylindrical form, with one face perpendicular to the cylinder axis and having a frustospherical concavity concentric with said axis, the opposite face having a continuous series of parallel, isosceles serrations arranged chord-wise of the cylinder, and disposed at an angle to said one face.

3. A height compensating device for table legs and the like comprising a pair of wedges, each of generally rightcircular, cylindrical form, with one face perpendicular 3 4 to the cylinder axis, and having a frusto-spherical com posite face having a continuous series of parallel serracavity concentric with said axis, the opposite face having tions arranged chord-wise of the cylinder. a continuous series of parallel serrations arranged chordwise of the cylinder, and disposed at an angle to said one Referenc s Cited in the file Of this patent face. 5 y

4. A height compensating device for table legs and UNITED STATES PATENTS the like comprising a pair of cylindrical wedges, ea h hav- 1331766 Easterly 10, 1872 ing one face perpendicular to the cylinder axis and 2, 8 3 Matter 111116 9 the opposite face disposed at an angle to said one face, 2,709,571 Mafera May 31, 1955 said one face having a central concavity and said op- 10 2,772,596 Trussell Dec. 4, 1956 

